Thanks for posting this topic but it really did not helped the specific question. Actually your answer will only help if the intention is to upload photo from mac/pc to iphone not the other way that is from iphone to device.
Also i see it more useful to just download photos on the device from phone rather than other way. So if i want to upload old photo from my iphone before setting up icloud. Its not explained under icloud.com help. Infact All help documentation i read icloud.com only tell you how to do it from mac or pc to phone. or of course if you take new photo they go directly to my device.
I want to know how to push old photos from iphone to photostream so they get downloaded to my device not the other way.
I could do this from box.net but that defeats the purpose of having icloud. Or maybe apple just want us to figure out some other way(manual) to move old photo to the device. Not sure why it was not thought of or explained properly.
Also I hear barryfromseattle frustration because I went through the same excercise later on to realize photo stream is not really a backup service but just an easier mechanism to share your new photo(after icloud is setup) from mutiple iphone/ipad to a central device. Note that its not a storage or backup service since its wiping off all new photo after 30 days.